Fuse



v 30 fully exposed Patented Oct. 30, 192,8.

ITED STATES A '1,689,424 PATENT OFFICE..

:NICHOLAS J. coNaAn, or WILMETTE, ILLINOIS, AssIeNOa To scnwnITzna aCONRAD,

ING., or cIIIoAGO, ILLINOIS, A OORPORATION'OI ILLINOIS. l

rusa.

Application led Kay 17,

My 'invention relates to uses, v particularlyto the type such asdisclosed in 'Conrad Patent 1,220,152' of March 20, 1917, or Schweitzer& Conrad Patent Number 1,319,-

907 Of'October 28, 1919, inwhich type a transparent housing usuallyinthe form of a glass tube is used for enclosing the fuse and circuitrupturing parts and the arc extinguishing liquid.

Glass is a very desirable material Jfor enclosing the circuitcontrolling parts of the fuse structurey as it has the necessarymechanical strength, 'is sufficiently electrically resistant, resist-schemical 'attack by i5 the arc extinguishing fluid, and is transparentso that the contents of the glass housing can always be observed.Hereto-.

fore, plaln uncolored glass has been used and such uncolored glass hasdisadvantages which it is the important Object of my present inventionto overcome. Arc extinguishing fluid, particularly carbon tetra chloridehas a tendency to attack substances, particularly metal, and such actionis greatlyA ina5 creased in the resence of light. The fuses to which myinvention apply are used in connection with high voltage transmissionlinesY where the transformer or substations are out in the open so thatthe fuses are to the weather and to full sunlight. This intense lightcan readily pass through the uncolored glass and will hastendeterioration of the are extinguishing fluid and its action on metalsand other substances within the fuse structure. The chemical Or actinicrays o f light are the ones which cause such action of the fluid, suchrays pass readily throughuncolored glass.

I have found that by using colored glass, 0 as for example, green, red,orange, Or ruby colored glass, these chemical or harmful rays areintercepted and prevented from iniluencing the arc extinguishing fluid.

In Order to illustrate the application of my invention I have shown aVuse structure on the accompanying drawing. On the drawing, 'y Figure 1is a side elevational view of a fuse structure partly in verticaldiametral v section; andl Fig. 2 is a top view. Briefly describ'ng thestructure, 1 represents the enclosing glass tube which has at its lowerend the terminal cap 2 and at its upper end the terminal cap structure3, these has the diametral slot 20 for receiving fthe 192s. seriai No.109,814..

cap structures being rigidly sealed to the tube end. The lower capstructure has the vaxial lug 4 which is threaded to receive the Vthelower end of this upper terminal post.

The tension spring 10 is anchored by means of pin 11 to the collar12'which is secured to the lower terminal post 5 as by means of a screw13. At its upper end the spring is secured byv pin 14 to the collar'15which is secured by screw 16 to upper terminal post 8. -On the interiorannular shoulder 17 formed on the terminal cap 3 above the end ofv lthetube 1 rests the annular support 18 75 for the washer 19, this washerbeing of in; sulating material such las bakelite. The upper ond of theupper terminal post 8 extends into and is slidable in the washer 19 andBI) fuse structure 21 which is secured at its diametrical opposite endsto the cap structure 3 by means of the screws 22. This fuse structuremay be of the ty e disclosed in m co-pending application erial No. 32,-740 filed May 25, 1925, and normally holds the upper terminal postS inits upper position against the pull of the spring 10. Above the fusestructure the annular recess 23 in the cap structure 3 seats the ventcover 24 which with the adjacent walls of the cap structure 3 forms theexplosion chamber 25 above the fuse structure. The tube 1 is filled witharc extinguishing fluid 26 such as carbon tetra chloride and this'liquid10 normally extends up to the washer 19. l

The fuse structure is placed in service with its terminal caps inengagement with the terminals of a circuit to be protected, and uponabnormal current low through the circuit, the fuse structure 21 willfuse and the upper terminal post 8 will be released whereupon the spring10 will forcibly draw down the upper terminal post and with it theplunger 7. The plunger vhas the annular convergent or nozzle passagewayaround the upper terminal ost so that when the plunger is Iforcibly sudonly drawn downwardly in the tube 1 the extin ishing fluid will besquirted upwardly vio ently to effectively ex- 11o t-inguish and destroyany arcing which might tend to take place after rupture of the fusestructure .and downward movement of the upper terminal post.

Some fluids, as for example, halogen dervatives of hydro-carbon, andparticularly carbon tetra chloride, have a tendency to attack metals andother materials and this action is greatly increased and hastened in thepresence of strong light. Where the fuses are placed in dark places,such action is not so noticeable, but fuses of the types described areused in outdoor substations or transformer stations and are exposeddirectly to strong sunlight, and under such conditions of service afluid such as carbon tetra chloride is under a disadvantage, and theincreased activity in attacking materials in contact therewith and itstendency to disintegrate, detract from the eiiiciency and reliability ofthe fuse structure. The actinic or chemical rays of light are the oneswhich cause such action of the fluid, and where the glass of thesurrounding tube 1 is uncolored, these rays may readily pass through.Other material besides glass could be used lwhich could keep out lightentirely, but glass on account of its transparent quality is Verydesirable as it permits inspection of the fuse working part at alltimes. I therefore make it possible to retain the use of glass and tostill rotect the contained fluid against the actinic rays of light byusing colored glass or by applying coloring material to the primarilyuncolored glass. I find that with green, red, orange, or ruby coloredglass the actinic rays will be suiiiciently intercepted or renderedharmless, although there may be other colors which will serve the samepurpose. Such coloring will not interfere with vision through the glassfor inspecting the interior of the fuse structure at any time. Theassociation of a color medium with the fluid will protect it even in thestrongest sun or other light.

Having described my invention, I claim as follows In a device of theclass describedya pair of fuse terminals, a fuse element connectedbetween them, a spring for moving one of said terminals away from theother when the fuse melts, a iiuid tight casing for said element, saidcasing including a pair of external terminals and an intermediate glasstube within which the spring is disposed, a bath of are extinguishingliquid in said casing, said arc extinguishing liquid comprising ahalogenderivative of a hydrocarbon which is normally inert, but which,under the action of light, disintegrates and attacks the fuse, changingits capacity, said glass tube having embodied therein a substance whichscreens out the rays that tend to disintegrate the liquid` but permitssuliicient visible light to pass therethrough to permit the position ofthe spring to be seen to determine whether the fuse has blown or not.

In witness whereof, I hereunto subscribe my name this 15th day of May,1926.

' NICHOLAS J. CONRAD.

